This invention relates to local telephone service, and, more particularly, to the area of providing an economic, flexible transmission medium between the serving switch and remote line units.
The increase in the number of telephone lines in use has exceeded the expectations of even the most optimistic operating company. Such increases, while good for revenue, require operating companies to scramble for equipment to support all of the new telephone lines being installed throughout its service region. In predigital days, a new switching office was required every time a previous switching office""s capacity was exceeded. In more modern times, remote line units connected to a switching system via trunk group has increased the range and the capacity of modern switches. However, operating companies must provision their equipment for worst case (or near worst case) usage, which leads to overbuilding the system hence unnecessary cost.
An example of the current art is shown in FIG. 1. In a local service area 10, a telephone switching system (xe2x80x9cswitchxe2x80x9d) such as a 5ESS(copyright) switch manufactured by Lucent Technologies is connected to the public switch telephone network (PSTN) 14 via a plurality of lines and trunk groups. The PSTN 14 comprises other local switches, long distance switches, wireless systems, etc. In order to support the diverse residential and business locations a telephone switch 12 is connected to one or more subscriber loop carriers illustrated here by subscriber loop carrier (SLC) 16 and 18. Subscriber loop carrier 16 serves analog (plain old telephone service or POTS) telephones 20 and 22 and ISDN telephone 24 in residential area 26. Subscriber loop carrier 18 is shown as supporting a plurality of telephone systems represented by POTS telephone 30 and ISDN telephones 32 and 34 in business campus 36. Each SLC 16 and 18 provides the basic battery, over voltage, ringing, supervision, hybrid and testing (BORSHT) functions for its respective subscriber telephones and multiplexes traffic for their respective subscriber telephones on trunk groups 40 and 42, respectively. In the current art, trunk groups 40 and 42 are optical trunk groups that have a large bandwidth. Each trunk 40 and 42 is connect to a host terminal 44 and 46. Host terminals 44 and 46 provide conversion of calls from the transmission format to a line appearance at telephone switch 12. In this manner, calls. destined, for example, for telephone 20 appears to telephone switch 12 to be a line directly connected to switch 12.
A problem in the art, however, is that the maximum anticipated traffic must be supported by both subscriber loop carrier 16 and subscriber loop carrier 18. Therefore, the business campus must be able to support maximum usage (usually, Monday morning between the hours of 9:00 and 11:00) and thus host terminal 46, trunk 42 and subscriber loop carrier 18 must have the capacity to carry such traffic. Conversely, residential area 26 must be engineered to carry traffic for peak usage days (such as Mother""s Day, Christmas Day, etc.) expected in the residential area. Thus, host terminal 44, trunk 40 and subscriber loop carrier 16 are engineered to a maximum bandwidth capacity for such traffic.
From the above scenario, it is clear that the operating company of telephone switch 12 has capacity that it is not using. When telephone usage at the business campus is at its peak, the residential area 26 is generally at its lowest. Conversely, when residential usage 26 is at its peak, telephones on the business campus 36 is not in high use. Thus, depending on the time of day (and day of the week) much of the capacity of one or the other subscriber loop carrier 16 or 18 is being underutilized while, conversely, the capacity of the other subscriber loop carrier is being pushed near its limit.
Therefore, a problem in the art is that there is no dynamic, flexible manner in which to allocate bandwidth to remote subscriber loop carriers
This problem is solved and a technical advance is achieved in the art by a system and method that uses the flexible bandwidth of a data network in order to provide more flexible services to wireline terminals. The system comprises a telephone switch configured to provide telephony service to a plurality of wireline terminals and an access network head end connected via circuit switch transmission facilities to the telephone switch and configured to manage reserved data bandwidth (xe2x80x9cbearer channelsxe2x80x9d) in a data network. The system also includes a data network carrying the bearer channels and a line unit separate from the telephone switch connected to the data network and to the wireline terminals configured to interface wireline terminals to one of the bearer channels. The access network head end has a controller having a table for translating line identification to a line unit address in the data network. The access network head end allocates a portion of its reserved bandwidth to each remote line unit with which it is associated. The amount of bandwidth is variable so that the access network head end can change the allocation to support changing traffic patterns according to time of day, day of week, etc.